Condenser telephone



y 1929. J. UN;I'ERHYOLZNER 7,

CONDENSER TELEPHONE:

Original Filed Aug. 13, 1912 INVENTOR BQWAWW ATTORNEYS @567 aide/"M21261 Reissued July 2, 1929.

UNITED STATES Re. 17,349 PATENT OFFICE.

' JosEF UNTERHOLZNER, or MUNICH, GERMANY, 'ASSIGNOR, BY MEsN'E ASSIGNMENTS,

' '10 WILLIAM roan-or WOODSBURGH, NEW .YORK.

CONDENSER TELEPHONE.

Original No. 1,082,248, dated December 2a, 1913, Serial No. 714,756,.fi1ed August is, 1912', and in" Germany August 28, 1911.

The invention relates to improvements in condenser-telephones and. the object of the invention is a condenser-telephone permitting a specially clear and loud transmission of sounds. There are known mechanisms producing waves of sound by means ofa diaphragm and an electrified condenser plate. In,those mechanisms the vibrations of the diaphragm are deadened by the thin stratum of air between the diaphragm and the condenser-plate. In replacing the impermeable condenser-plate by a perforated plate or grid, the invention in question avoids the said disadvantage and allows at the same timeto influence the diaphragm from both sides the use of two grids instead of the onlycondensenplate.

The invention is represented in the accompanying drawing.

Figure 1 shows a simple condenser-telephone with the scheme of the electric connection according to the invention, Fig. 2 is a combined condenser-telephone.

Between two differently charged grids, a

and c a diaphragm b is arranged, which must not be necessarily elastic, (foil or COD". ducting tissue, for instance) and which is caused to vibrate by means of the micro phone-transformer. To increase the vigor of sounds a sufiicient space of air G may be provided.

The mode of action of this condenser-telephone is asfollows: The wave-current probe attained in. three duces alternating charges which cause the diaphragm to be attracted by the one grid and repulsed by the other. In this way the diaphragm is caused to vibrate and the vibrations are transmitted through the grids into the air. The eflicacy of the telephone remains the same if the diaphra m is charged and the grids are influenced by the transformer. In the same manner di-electric grids with aconducting diaphragm, or a dielectric diaphragm ,with conducting grids can be used for production of sounds, if the gielectric is charged for instance by rubmg.

The insulation of gridsand diaphragm can .ways: 1, by insulating spaces; 2, by insulating the grids; .3, by insulating the diaphragm. Another possibility of connecting consists in charging the grid a and the'di'aphragm b in one sense and the grid 0 in the other sense,

both systems be- Application for reissue filed March 13, 1929. Serial No. 346,774.

ing influenced by the 'microphonetrans- An increased reproduction of sounds can be attained by combining several condensertelephones to a multiple condenser-telephone or telephone-battery, as shown in Fig. 2. In this case all the grids a are charged in one sense, all the grids c inthe' other sense. The diaphragms b are connected with one end of the secondary winding of the transformer, the diaphragms d with the other end of it Again a sufficient space of air 0 may be added. p

The increased eiiicacy of the battery is due to the circumstance, that at any phase of the undulatory current, the diaphragms b as well as the diaphragms d vibrate in the same direction, thus acting so upon each other that a larger amplitude and therefore a higher effect is attained.

What I claim is: V 1. A telephone of the character specified for directly translating modulated electric currents into audible sound, embodying therein an imperforate diaphragm, and a perforated electrically charged condenser member operatively associated therewith, substantially as described.

2. A telephone of the character specified for directly translating modulated electrifsg ..between said members, substantially as described. I V

4. A telephone of the character specified, embodying therein a pluralit of parallel diaphragms, a positively electrically charged perforated condenser member at one side of each diaphragm, and a negatively charged perforated condenser member at the opposite side of each diaphragm, substantially as described. I r r 5. 'A telephone of the character specified, embodying therein a casing provided with an air space, a diaphragm carried by said c'asin a microphone transformer connected wig said diaphragm, and a perforated condenser member operatively associated with said diaphragm, substantially as described.

6. A telephone of the character specified, embodying therein a casing provided with an air space, a diaphragm carried by said casing, a microphone transformer connected with said diaphragm, and a perforated condenser member at each side of-said diaphragm, said condenser members-being oppositely charged electrically.

7. In a condenser telephone for directly 9. In a condenser telephone, imperforate diaphragm means comprising areas of conductive foil, perforated electrically chargedgrid condenser means, said diaphragm means and condenser means being operatively associated and relatively closely spaced by air pockets and insulating means, the perforations of the'condenser means being effective to lessen the dampening action of the air pockets.

10. A telephone of the character specified for directly translating modulated electric currents into audible sound, embodying therein an imperforate diaphragm, and an electrically charged condenser member oper- -.atively associated therewith, said member having numerous relatively small perforations distributed over its area.

. distributed over its area and communicative with the air between said diaphragm and said conductive foil supported along an 11. In a condenser telephone, an imperforate diaphragm area comprising conducting foil, and an electrically charged condenser member operatively associated therewith, and extending closely adjacent to one surface of the diaphragm but separated therefrom" by air and other insulating means, said member having perforations distributed over its area, said perforations being communicative with the air between diaphragm and condenser member.

12. A telephone of the character specified, embodying an imperforate diaphra 'lof re atively closely adj acentto a surface area of an electrically charged condenser member and insulated therefrom by means including air,

said member having numerous perforations member.

13. Acondenser telephone, embodying supporting means having'an .air cavity at one side of which a plurality of operatively associated condenser members are mounted face to face, one of said members comprising an imperforate diaphragm, another of said members comprising a perforated electrically charged condenser member, the perforations of which communicate with the air of said Igavity and with air space between said me1ners.

14. A telephone of the character specified for directly translating modulated electric currents into audible sound, embodying therein an imperforate diaphragm, and an electrically charged condenser member operatively associated therewith, said member having numerous perforations distributed over substantially its entire effective area which directly cooperates with the diaphragm.

' 15. A condenser telephone embodying an imperforate diaphragm of insulated conductive foil supported along a surface area of an electrically charged condenser member, said member having numerous closely adjacent perforations distributed over its area to provide a grid construction.

16. A condenser telephone embodying an imperforate diaphragm of conductive foil supported between and relatively closely adjacent to surface areas of a pair of electrically charged condenser members, said members having numerous closely adjacent perforations distributed over their areas to provide grid constructions.

17. A condenser telephone embodying an imperforate diaphragm of insulated conductive;foil extending along a surface area of an electrically charged condenser member, said member having numerous closely ad- .jacent perforations distributed-over substantially its entire area as opposed in cooperative relationship with the diaphragm.

.18. A condenser telephone embodying an imperforate diaphragm of conductive foil supported between and relatively closely adjacent to surface areas of a pair of electrical-. v

lycharged condenser members, said members having numerous closely adjacent perforations distributed over substantially their entire areas as opposed in cooperative relationship with the diaphragm.

19. A condenser telephone embodying an imperforate diaphragm of foil supported along a surface area of an electrically charged condenser member, said member having numerous closely adjacent perforations substantially uniformly distributed over its area 'to provide a grid construction.

. 20. A condenser telephone embodying an imperforate electrically charged diaphragm,

and another electrically charged condenser member operatively" associated therewith, I

said last named member having numerous a closely adjacent perforations distributed over substantially its entire area as opposed in cooperative relationship with vibratory portions of said diaphragm, said perforations in area amounting to a substantial proportion of the total areaof the member,

21. A condenser telephone embodying an imperforate electrically charged diaphragm, and another electrically; charged condenser member operatively associated therewith,

said last named member aving numerous closely ad acent perlora't ons (hstrlbuted' over its area as opposed in cooperative relationship with v1bratoryp0rt1ons of said diaphragm,

said perforations each being quite small as compared to the total area of said member but n the aggregate amounting to a. substantial proportion-of the total area of the member.

an another electrically charged condenser member oper'atively associated therewith, said last named member having numerous vclosely adjacent perforations distributed over its area as opposed in oooperative relationship with vibratory portions ofisaid diaphragm, saidperforations'being spaced at distances in the neighborhood of the Widths of the perforations.

-In testimony "whereofiI have signedmy name to this specificationf JOSEF UNTERHQLZNER. 

